1220 filter and handle missing entries in the validation module

[EinarElen]

I am updating ldmx-sw, here are the details.

I've added two new command line parameters for the validation module, one which lets you specify exactly which files you want to compare (as opposed to all files in the input data directory). You can either specify the name of a file in the input directory or give the entire path to the file. The other parameter lets you filter the list of root-files (a use-case for this in my case would be filtering on the number of events in a pile of files).

Also added an exception handling step in Differ to handle missing histograms gracefully.

Example usage:
Assuming you have three files in the hists/ folder

• ecal_trunk_10000_events.root
• ecal_trunk_100_events.root
• ecal_PR_10000_events.root
• hcal_trunk_10000_events.root

Running

ldmx python3 -m Validation hists --input-files ecal_trunk_10000_events.root hists/ecal_PR_10000_events.root  ...

Would only plot the two ecal files with 10k events
Running

ldmx python3 -m Validation hists --input-file-filter="ecal" ...

Would use the three files including "ecal" in the name

etc

What are the issues that this addresses?

Hint: Use the phrase 'This resolves #< issue number >' so that they are linked automatically.
This resolves #1220

Check List

• I successfully compiled ldmx-sw with my developments

• I ran my developments and the following shows that they are successful.
  Tested both the new parameters and handling of missing histograms. Worked like a charm :)

• I attached any sub-module related changes to this PR.
  N/A

Related Sub-Module PRs

N/A

[tomeichlersmith]

I have one suggestion but it is minor and may not be worth it.

In general, I like this feature improvement and I'm glad to see that folks are using the Validation module!